eChapters

Learning outcomes

1. To make student aware about proper procedure of conducting oral and poster presentation and to develop their skill in delivering effective presentation.

What is presentation?

• Presentation is the process of demonstrating and conveying a topic’s information to an audience or learner.
• Presentation may be customised for speaking to a group, addressing a meeting, or briefing a team.

Making oral presentations is nothing new for anyone, but there is still a lot of room for growth. An oral presentation is more than simply delivering the relevant technical information and using the perfect language. Public speaking is an address delivered at an anniversary or inauguration to encourage, congratulate, or amuse the audience.

1.0. Objectives

• To impart knowledge of Phonetic and phonology and the significance of its taching and learning
• To make understand how sounds of the alphabets are made and perceived
• To demonstrate the use of the phonetics material

2.0 Introduction to Phonetics

Phonetics is a branch of Linguistics. It is a word derived from the Greek word, phone= sound/ voice. It is the study of sounds and the human voice.

Phonology is the study of sound patterns of a particular language.

1.0. Objectives

• To describe how to develop thoughts in various situations
• To manifest the methods to judge the mind of people
• To make learners familiar with ready sentences
• To practice to imagine the consequence of conversation
• To learn to use interrogative adverbs effectively
• Impart the manner to utter information, ideas, and concepts in a more polite way

1.0. Objectives

• To impart knowledge of intonation, its types and pitch in sentences
• To identify stress on words in sentences.
• To understand how stress on words changes the meaning
• To impart knowledge of intonation symbols
• To develop the ability to recognize the intonation and acquire speech and its pattern

2.0. Definition

Intonation is the variation that takes place in the pitch of the voice in connected speech i.e. the variation in the pitch of the musical note produced by the vibration of the vocal cords. It is melody in spoken language.

Sodium Clinical Significance Compared to potassium, sodium is distributed differently throughout the body. Due to the sodium pump mechanism, most sodium is extracellular. Compared to this, just 2% of potassium is extracellular; the remainder is intracellular. Regarding the plasma concentrations of sodium and potassium, renal function is the single most significant homeostatic mechanism.

Emerging Paradigm of Extension Plus:

This is now widely recognized that Animal Husbandry extension needs to reform in ways that allow it to fulfill a diverse set of objectives in worldwide. This ranges from better linking of farmers to input and output markets, to reducing the vulnerability and enhancing voice of the rural poor, development of micro-enterprises, poverty reduction and environmental conservation and strengthening and support of farmer organizations’. So while technology transfer is important, what is also required is the strengthening of locally relevant innovation processes and knowledge systems. Extension is being forced to embrace a broadened mandate that while in reality has always existed, has rarely been addressed. The limitations of a single model of extension for all kinds of situations are now well recognized and there is an increasing realization that new extension approaches need to emerge locally, based on experimentation, learning and adaptation to prevailing circumstances. The need for this new and expanded view of extension is clearly emerging in the case of Indian agriculture, which is characterized by declining land and water availability, degradation of natural resources, an unfavorable price regime, low value addition, particularly in rural areas and increasing competition from import of agricultural commodities. Farmers thus find themselves in an ever more complex production and market environment, with an expanding need for information and services.

Milk, meat, eggs and their products have been the important part of the human diet in almost all countries of the world. These are highly nutritious and provide vital nutrients absent in typical starchy staples which dominate poor people’s diets. On global scale, animal meat, egg and milk provide 80% of animal protein intake.

The livestock sector requires a significant amount of natural resources and is responsible for about 14.5% of total anthropogenic greenhouse gas emissions (7.1 Gigatonnes of carbon dioxide equivalents for the year 2005). Methane, mainly produced by enteric fermentation and manure storage, is a gas which has an effect on global warming 28 times higher than carbon dioxide. Nitrous oxide, arising from manure storage and the use of organic/inorganic fertilizers, is a molecule with a global warming potential 265 times higher than carbon dioxide. The carbon dioxide equivalent is a standard unit used to account for the global warming potential. Mitigation strategies aimed at reducing emissions of this sector are needed to limit the environmental burden from food production while ensuring a sufficient supply of food for a growing world population.

Introduction

In agriculture, Knowledge and decision-making capacity determine how production factors like soil water and capital are utilized in judicious manner. Agricultural Extension System remains in central position for formulating and disseminating knowledge including hands on training to the farmers. Realizing the scope and importance of integrated working of inter relationship between research, education and extension functions, the ICAR established a section of extension education at its head quarter in 1971 which was later on strengthen and renamed as Division of Agricultural Extension. Extension Education plays an important role in most of the Agricultural Development project. Moreover, Agricultural Extension is part of system of factors which influence farmer’s decision. It includes agricultural researchers, political authorities, farmer’s organization, non-govt. organizations, farmers training centre and media. These actors assume the functions of research, information dissemination, training and so on. The primary goal of agricultural extension is to assist farming families in adopting their production and marketing strategies to rapidly changing social, political and economic condition so that they can, in the long term, shape their lives according to their personal preferences and those of community.

Any kind of developmental programme needs a proper integration of different parts of the society i.e. stakeholders of that programme. Apart from the nodal body, many implementing agencies take part in the implementation, monitoring of those programmes. Non-Government Organizations are one of those who actively participated in developmental activities not only as an implementing agency but also in mobilizing the resources, proper utilizing that and also effectively utilizing the resource towards development. NonGovernment Organization is an organization that is independent in nature, politically, socially unbiased and has a proper legal stand with developmental orientation.

“Only those who attempt the absurd can achieve the impossible.”

- Albert Einstein

Motivation– An inner state of need or desire that activates an individual to do something that will satisfy that need or desire.

The processes that are responsible for an individual’s intensity, direction and persistence of effort toward attaining a goal.

Key Elements

1. Intensity: how hard a person tries
2. Direction: toward the beneficial goal
3. Persistence: how long a person tries

Introduction

Entrepreneurship assimilates a very decisive dynamic dimension in a modified form through the globalisation progression into the Indian economic system. The core strength of economic development and economic growth in all underdeveloped and developing nations around the world is only due to the presence of entrepreneurial activity. A successful entrepreneurial approach plays a crucial role in the progress of industrial, manufacturing and service sectors and the development of agriculture. The government of most developing countries have invested much effort and resources in the past to enrich entrepreneurship (Oni and Daniya, 2012). According to a recent study, Saudi Arabia has been attempting to build a ten-year innovation and efforts entrepreneurship programme starting the year 2010. Similarly, in Malaysia, the government guided to set up of several technologies through the growth of technological know-how in entrepreneurship.

Introduction

India’s change in the economic environment and market-oriented economic reforms can be traced back to the 1990s which led to the growth of the country. There was a clear evident change from the condition it was in the 1970s when it was far behind the other Asian countries. The economic reforms brought by LPG (Liberalisation, Privatisation and Globalisation) model have affected not only international trade but also led to an increase in the competitiveness of the industries. But what triggered these economic reforms? Before 1990, India was in a severe economic crisis condition due to repeated policy failures. India was experiencing a huge fiscal and balance of payment deficit, a high inflation rate and a fall in foreign exchange reserves. This led to the sickening of the public sector units whose prime role was to bring a reduction in inequality and poverty. The self-reliance condition in India was not of much help as there was insignificant trade with the rest of the world. The crisis mainly depicted the mismanagement of the resources. In light of this, this chapter discusses the impact of the economic reforms on agri-enterprises.

Successful management strategies require an understanding of the pig reproductive system. Profitability in pig production farm is primarily limited by reproductive efficiency. Increasing reproductive efficiency lowers the cost of each pig sold. Increased pig marketing per female could reduce the number of sows required or increase the overall number of pigs marketed per year. Nonetheless, improving reproductive performance requires time. There are no quick fixes for enhancing reproductive performance. To improve the reproductive parameters of swine farms, sound management approaches and a rigorous genetic selection programme are required.

Qualitative characters are those characters which show discontinuous or discrete differences and are counted into different classes and there is no need to measure them. Typically speaking, characters studied by Mendel in garden pea whose results were published in 1966 as Mendel’s Law were the typical characters that fitted into this class of characters in those days. To recall, these characters were (i) tall vs dwarf plants, (ii) round vs wrinkled seeds, (iii) yellow vs green pods, (iv) violet vs white flowers, (v) flat pods vs constricted pods, (vi), green pods vs yellow pods and (vii) axial flowers vs terminal flowers. Mendel postulated “Factors” responsible for these differences and he could explain his results of F₂ in ratio of 3:1 while dealing with one trait at a time and 9:3:3:1 while dealing with two traits simultaneously and proposed (i) law of segregation and (ii) principles of independent assortment to explain these ratios. Later on the term “factor” was called as gene.

Hybrid vigor or heterosis is opposite and complementary to inbreeding depression (reduction in fitness as a direct result of inbreeding). In theory, the heterosis observed after crossing is expected to be equal to the depression upon inbreeding, considering a large number of crosses between lines derived from a single base population. In practice, plant breeders are interested in heterosis expressed by specific crosses between selected parents, or between populations that have no known common recent origin. Furthermore, because heterosis is subject to the interactions between genotype and environment, it is desirable to describe the heterosis of a particular hybrid line for a specific trait at a specific location or under specified environmental conditions.

Recurrent selection is a method of breeding applicable to cross-pollinated crops, designed to concentrate favourable genes scattered among a number of individuals by selecting in each generation among the progeny produced by mating inter se of the selected individuals (or their selfed progeny) of the previous generation. The concept of recurrent selection grew out of need to increase the number of superior genotypes that could be obtained from breeding stock of corn. This could have been possible by increasing the frequency of superior genes in the gene pool and by increasing the chances for genetic recombination to occur. The original idea behind recurrent selection was proposed first by Hayes and Gerber in 1919 and independently by East and Jones in 1920. Jenkins (1940) was the first to describe the method in detail and Hull (1945) proposed the name ‘recurrent selection’. Each cycle of recurrent selection requires:

Any organism with other than two basic sets of chromosomes, that is, monoploid, triploid, tetraploid, and various aneuploids is termed as polyploid. There are several economically important crops which are natural polyploids emphasizing the economic importance of polyploids in agriculture. These are:

Triploid-Banana

Autotetraploid-Alfalfa, potato, coffee, peanut or groundnut Autohexaploid- Sweet potato

Amphidiploid/allopolyploid-Wheat, cotton, oats, Brassica species (B. carinata- Ethiopian mustard, B. juncea-Indian mustard, B. napus--rapeseed), sugarcane

Man-made commercially successful allopolyploid- Triticale

The term “Poultry” indicates to all the domesticated species of birds like chicken, ducks, turkeys, Japanese quail, guinea fowls, geese, pigeons, ostrich, emu etc. Ducks account for 7% of poultry population and are mostly found in coastal states of the country and in states with more lakes and rivers like West Bengal, Orissa, Andhra Pradesh, Tamil Nadu, Kerala, Assam, Jammu and Kashmir and Tripura. Duck farming is still in primitive stage and indigenous ducks outnumbered the exotic ducks in spite of their inferior performance.

In India 90-95% of ducks are indigenous or nondescript types, which are hardly, with mediocre egg production and highly suitable for extensive system of rearing.

Programme Coordinator, KVK, Gonikoppal, Karnataka

Horticultural extension also known as a horticultural advisory service plays a crucial role in boosting horticultural productivity, increasing food security, improving rural livelihoods and promoting horticulture as an engine of economic growth in rural areas. Horticultural Extension needs to provide a critical support service for rural farmers at the same time meeting the new challenges faced by them in their farming. Horticultural extension in remote and hilly terrains is difficult and time consuming, requiring some innovative methodologies to meet the farmers needs and expectations. At KVK we decided to experiment with an idea of a farmers collective organization, established and nurtured right from the beginning at KVK itself with support from its host organization (ICAR-IIHR, Bengaluru) and NABARD, Kodagu. 

Principal Scientist and I/c Head, Division of Social Sciences and Training, IIHR, Hessaraghatta Lake Post, Bangalore – 560 089, Karnataka

Business analytics focuses on data, statistical analysis and reporting to help investigate and analyze business performance, provide insights, and drive recommendations to improve performance.

What are the 4 types of business analytics?

Rural Economy and Agriculture

It is being progressively recognized that the globalized nature of economies across the world is affecting the economic security of all nations. Particularly, in this present era when globalization, liberalization and privatization are rapidly budding and creating new threats and opportunities, it is established that farmers need to be organized to participate and proliferate in the development processes. The phenomenon has triggered substantial debate as to whether globalization is positive evolution of economic action or detrimental to the interests of certain countries or specific groups (Kaplinsky, 2004; Nadvi, 2004).

A business plan is a document that summarises a company’s operational and financial goals. It is a road map to success for a business, with detailed plans and budgets outlining how the goals will be met. A business plan outlines how a company will achieve its objectives. A business plan is an essential first step for anyone starting a business. These concrete milestones will aid in tracking the company’s success (or lack thereof). There are various business plans for various purposes, and the best business plans are living documents that respond as quickly as possible to real-world factors.

A good business plan adheres to widely accepted guidelines in terms of both form and content. A business plan is divided into three sections:

• The first is the business concept, in which you discuss the industry, your business structure, your specific product or service, and your plans for success.

Introduction

The poultry industry is under pressure to produce safe and good quality meat in the welfare conditions. Many areas such as genetics, biosecurity, and immunoprophylaxis were improved, and hatchery is one of the areas in which welfare could be improved for better production output. Under commercial hatched conditions, poults hatch over a 36 to 48 hour period (called hatching window) and after additional processing are transported to the farm. Hatch window is the time gap from first chick hatched to last chick hatched (Noiva et al., 2014). This causes early hatched chicks to be deprived of feed for longer duration (Kadam etal., 2013). 

Introduction

Poultry industry is one of the quickest developing sectors in India. Poultry involves a remarkable position in the livestock economy of India by coexistence of intense technology, capital, and scale with integrated production, marketing and the others based on the traditional knowledge and practices. The annual growth rate is more than 11% and 8 % in broiler production and egg production respectively. The general development rate of poultry industry is around 7-8% for every annum, most outstanding among all sectors of agriculture. In poultry industry, poultry meat accounts for two third of the value of output and one third by eggs. 

1.1 Introduction

The life on the earth is driven by the energy available in the various forms. Energy is the most crucial entity in development of the world. The sufficient and sustainable supply of energy is deciding factor in the global energy market. Solar energy from the sun is the basic source of energy on the earth which further manifest into the other energy forms. However, the fossil fuel energy is widely used energy on the larger scale on commercial basis due to its availability and technological advancement in handling these fossil fuels.

6.1 Introduction

Biomass pellets are one of the most common types of biomass fuel. It is generally composed of wood waste, agricultural biomass, grasses, and forest residues, and is one of the most popular types of biomass fuel available today. Pelletization of biomass results in significant savings in terms of transportation, and storage, as well as the ease of handling biomass as a whole. In terms of flowability, dense cube pellets are similar to cereal grains in terms of their characteristics of being dense and cube-shaped. Due to their regular geometry and small size, biomass pellets are easily fed through an automatic feed system with fine calibration thanks to their regular shape. Because pellets are so dense, they can be stored in a compact way and transported over a long distance in a rational and efficient manner, because of their density. Furthermore, pellets can also be produced with a low moisture content, even though they are extremely dense. This allows them to burn with a high degree of combustion efficiency due to their low moisture content.

12.1 Introduction

A magneto hydrodynamic energy conversion system or MHD system converts heat energy directly into electricity. An MHD generator produces electricity via the interaction of a moving fluid with a magnetic field and ionized gas. MHD conversion does not involve any mechanical conversion intermediary. As a result, this process offers substantial fuel savings because the process of producing mechanical energy and then converting it to electrical energy is eliminated. It is possible to generate electricity in large quantities using MHD power plants while reducing the impact on the environment. During his Bakerian lecture in 1832 to the Royal Society, Michael Faraday presented the concept of MHD power generation for the very first time. 

3.1 Introduction

One of the most important functions to the AAS units is to widely disseminate the advisory bulletins among the user community. A unit cannot be considered operational unless its bulletins are reaching the target masses. The dissemination is one way communication which is broadly speaking the process by which human beings share information, knowledge, experience, ideas and motivation. 

4.1 Introduction

The livestock/poultry have great capability for climatic adaptation and acclimatization. However in an open environmental condition their overall well-being and efficiency depends on day-to- day weather conditions. While certain breeds of livestock and poultry are considerably flexible to adjust themselves with the varying weather conditions, the others may have little adjustability. This has led to the development of weather/climate based livestock/ poultry management practices which include the general care. Nutrition and health managements for optimizing conditions for best yield in respect of milk, meat, eggs, wool, load carrying capacity etc. have been properly documented. 

Pulses are widely acknowledged as superfoods, three times the protein in rice and double in wheat. Besides, they are also rich in complex carbohydrates, micronutrients, protein and B-vitamins and minerals like folate, iron, calcium, magnesium, zinc and potassium. High iron content in some pulses also minimizes the risk of anaemia. Long storability without loss of nutritional value, low prices, and broader availability make pulses an affordable source of minerals, and protein, thus contributing to food security at all levels of society in India. Besides human nutrition, pulse crops are also utilized as fodder and fuel for farm households.

The informal associations of individuals who come close to seeking ways to enhance their living conditions are known as Self Help Groups (SHGs). They are generally self-governed and peer-controlled. An NGO or Agency usually governs people of comparable economic and social backgrounds to resolve their issues and improve their living conditions. It is a local committee of 10 to 20 women or men between 18 to 40 years. It acts as an intermediary financial committee. Self-help groups are a gaggle of each person on daily wages, and among that group, one person collects the cash and provides the case desired to the person in need.

s per the advancement in technology, our society is steadily moving towards adapting the new ordinary technologies for their normal affirms of life. While many’s daily lives are far from ordinary, one critical enabler for humans to survive and sustain their livelihood has been the accelerated adoption of digital technologies, especially in the last two years. We have witnessed how things happened because of the emerging technology in various sectors: education, business, communication, interaction, socialization, professional work, agriculture, etc. This will be the norm for the new normal and the “Gig Economy” evolution. Technology disruption has helped almost everyone in their many walks of life. When we consider the rural women at large, technology has, directly and indirectly, helped each procure food and other commodities to manage their livelihood. 

Empowerment in the women’s development context can be defined as defining, challenging, and overcoming the hurdles in women’s life. She enhances her ability to mould her life, personality, and surrounding environment. The buzzword “empowerment” synchronises with women metaphorically when we think of women empowerment. Such has been the issue and its importance in society today. However, why it matters so much can be attributed to “constraints”. 

Programme Development

Programme development is an on-going dynamic process that extension professionals intuitively follow as they plan, implement and evaluate their educational programmes. The process is not confined to a five-year planning cycle. It is applied on a small scale as an individual workshop is being developed, on a larger scale as a series of programmes are being developed around a single priority and on an even larger scale at district level and state level wide team sets priorities and defines a plan of action for a five-year period. The basic principles remain the same, only the scope is different. The gap between the situation and objective is the area of needs. This area becomes well-defined after the situations and the objectives are determined by the leaders, extension professionals and specialists.

First Line Extension system

Realizing the scope and importance of integrated working of interrelationship between research, education and extension functions, the ICAR established a section of Extension Education at its headquarters in 1971, which was later on strengthen and renamed as division of agriculture extension. It was intended to enforces this functional relationship down the line in the research institute, agricultural universities and allied institutions.

Community

1. A community is a group of people, who live in a geographical area and have an interest in each other for the purpose of making a living. It is a form of social organization existing between the family and state.
2. The people with common interests living in a particular area
3. An interacting population of various kinds of individuals (as species) in a common location
4. A group of people with a common characteristic or interest living together within a larger society

Agri portals

• Website that serves as a gateway or a main entry point (‘cyber door’) on the internet to a specific field of interest or an industry.
• A portal provides at least four essential services.
  1. Search engine(s).
  2. Email.
  3. Links to other related sites and.
  4. Personalized content.
  5. It may also provide other facilities such as chat, members list, free downloads, etc.

Training Need Assessment

Training Need Assessment (TNA) is the method of determining if a training need exists and, if it does, what training is required to fill the gap. TNA seeks to identify accurately the levels of the present situation in the target surveys, interview, observation, secondary data and workshop.

An assessment process that serves as a diagnostic tool for determining what training needs to take place. 

Introduction

Apomixis is a phenomenon in which there is development of seed without fertilization or sexual fusion. Embryo develops without fertilization in apomixis. Hence, apomixis is an asexual means of reproduction therefore the genotype of plant will be same as of mother plant. Apomixis was first time discovered by Leuwenhock in 1719 in citrus whereas the term apomixis was first time used by Winker in 1908.The main benefit of apomixis over sexual reproduction is the selection of individual plant with superior characters and propagation of clonally through seeds. Higher plants commonly exhibit apomixis. There are more than 300 species belonging to 35 families that exhibit apomixis. Most commonly, it occurs in Gramineae, Compositae, Rosaceae, and Rutaceae.

A nursery is a place, where seedling, saplings, trees, shrubs and other plant materials are raised and sold out for planting in gardens and orchards. The prerequisites of a successful and remunerative fruit production are the availability of true-type, healthy and good quality planting materials. Nursery is, therefore, a place where one can produce true to type plants by gaining technical skill, maintaining plants property and by careful planning. Like orchard establishment, establishment of a nursery is also at permanent venture and any mistake made initially can’t be rectified easily in the later stages. Therefore, for establishing a nursery, due care in selection of site, plants to be raised and transportation facilitation etc. must be given.

Nurserymen and propagators propagate different types of horticulture plants with seeds, cuttings, and other methods. Regardless of the medium used, an ideal medium should have the following characteristics:

1. The medium should be sufficient firm and dense to told seed or cutting or layer firmly in place during germination or rooting.
2. The volume of the medium should remain constant upon drying or wetting.
3. This medium should be able to hold and deliver an adequate amount of moisture to the seeds, cuttings or layers.

1. Determination of qualitative nursery planting materials

1.1 Quality assessment of seedlings

Nursery is a place where young/infant seedlings are kept under intensive care until they are ready for planting. The production of quality seedlings begins with the collection of quality seed, nursery establishment, and after-germination maintenance. The quality of plant propagation structures may not be a qualitatively gradable criterion, but it can be indirectly assessed by their relationship to growth, productivity, and vigour. The Dickson Quality Index (DQI) is very useful for assessing the quality of a specific group of seedlings. This is done by selecting some seedlings at random from that group and computing Dickson Quality Index (DQI).

Agriculture is under increasing pressure to produce more food, feed, and biofuel from limited land resources. The current over-reliance on a few key staple crops causes a variety of agronomic, ecological, nutritional, and economic issues and is likely unsustainable in the long run.

Vegetables have a high commercial value in general and hence contribute significantly to household income. Significant research, breeding, and development initiatives are necessary for a number of promising crops to transform existing local landraces into competitive cultivars with broad adaptability and high commercial prospects. India has a good genetic wealth of domesticated crops, and 600 plant species represent the diversity in vegetable crops out of 20,000 angiosperm plants; however, only one-fourth of these are used as major vegetable crops, with the rest classified as minor, underutilized/neglected, rare vegetables, lesser-known vegetables, wild edible vegetables, and so on. Access to the genetic diversity of these selected crops is required for success

Asparagus is an herbaceous perennial that is widely grown in the United States, Germany, Spain, and France, with India contributing only a little amount. For many years, asparagus has been grown. This was a favourite crop of the Ancient Greeks and Romans. It belongs to the Liliaceae family and is thought to have originated in the eastern Mediterranean and further east in the Caucasus Mountains. It’s a monocotyledonous perennial that’s farmed for its edible stems (spears).

Lima beans are flat green or light green beans. It is only utilised for the seed because the pods are coarse or woody. There are two kinds used in commercial canning: a climbing or pole variant and a dwarf or bush variation. Like other legumes used for seed, the lima bean (Phaseolus Iunatus) has a wide range in seed size, shape, and colour, as well as plant structure and primary applications. For freezing, canning, or fresh market usage, mature seeds are utilised like a vegetable. Lima’s have long been used as a grain legume when they are firm and dry. Peru is where they were discovered. The first domestication occurred in the Andes around 2000 BC, resulting in a large-seeded variety (Lima type), while the second occurred around 800 A.D. in Mesoamerica, resulting in a small-seeded variation (Sieva type).

Pigeon pea seeds discovered in historical tombs suggest it was farmed in Egypt circa 2000 BC. Vavilov (1939) concluded that India is the primary origin of the cultivated pigeon pea due to the wide diversity of germplasm available. It’s a crucial location in rain-fed agriculture. It is grown on 4.92 million hectares worldwide, including 3.58 million hectares (72.7 percent) in India alone. Although the crop is planted in 22 nations, it is only cultivated in considerable areas in a handful of them. Its seeds have become a widespread food in Asia, Africa, and Latin America since its domestication in the Indian subcontinent at least 3,500 years ago. It is an important source of protein for the Indian subcontinent’s people and is consumed on a big scale in South Asia. India is a major producer of pigeon peas. Kenya, Malawi, Uganda, Mozambique, and Tanzania are major producers of pigeon pea on the African continent.

Soils vary greatly in their organic matter content. For all practical purposes the organic matter content of the soil parallels the soil N content. The C/N ratio of soil organic matter generally falls in the range of 10 to 12. Because of the ease with which Kjeldahl determination can be made, N is often used as an index of soil organic matter content.

3.1. Composition of Organic Matter in Soil

Organic matter constitutes 1 to 6% of the topsoil weight of most upland soils. In a typical grassland soil, 5 to 6% of organic matter may be present in the top 15 cm. Top soils with less than 1% organic matter are mostly limited to desert regions. On the contrary, the organic matter content of soils in low, wet areas may be as high as 90% or even more. Soils with more than 12 - 18% organic carbon (approximately 20 - 30% organic matter) are called organic soils.

Soil is the product of various soil forming factors acting on the parent material over a period of time. The parent material is usually devoid of organic matter and consists of variable quantities of sand, silt, clay and carbonates. High temperatures and adequate moisture promote mineral transformations, but these effects are magnified by living organisms and the organic substances they produce. The biosphere and the organic substances they produce are directly or indirectly responsible for the following:

1. Decay of organic matter by microbes leads to the formation of CO₂ which is quantitatively the most important “aggressive” weathering agent because of its tendency to form carbonic acid with water [CO₂ + H₂O → H₂CO₃].

The synthesis of humic substances is the least understood and the most intriguing aspect of humus chemistry. This has been one of the intensely- researched subjects for a long time. Formation of humic substances takes several pathways during the decay of plant and animal remains in soil and the four important ones are shown in Fig. 8.1.

Fig. 8.1: Mechanisms for the formation of soil humic substances

The classical theory by Waksman advocated humic substances as modified lignins (Pathway 1), but a vast majority of current crop of investigators favour a mechanism involving quinones (Pathways 2 and 3). Including sugar-amine condensation pathway (Pathway 4), all the four pathways must be considered as likely mechanisms for the synthesis of humic and fulvic acids in nature. It is absolutely possible that these four pathways may operate in all soils, though not to the same extent or in the same order of importance.